Transcript Bluetooth 技術篇 • 藍芽技術如何傳輸資料 藍芽傳輸的安全性

Bluetooth 技術篇
• 藍芽技術如何傳輸資料
• 藍芽傳輸的安全性
第六組
吳哲榮
如何傳輸資料
1.信號與系統
類比調變與數位調變
2.設備位置(Device Addressing)
3.實體通道(Physical channel)
4.跳頻(Frequency Hopping)
5.時序同步(Master and Slave)
6.Piconet and Scatternet
7.資料傳輸形態(SCO and ACL)
類比調變or數位調變?!
ANS：
數位調變
(Digital Modulation)
Why?
1.抗干擾能力佳
- 訊號只有0與1
2.資料傳輸統合
- Data、Voice、Video
3.數位編碼加密
- Encryption
Device Addressing
1.BD_ADDR
NAP(not important)+UAP(hopping)+LAP(unique)
2.AM_ADDR
Active Member Address
MAX：8
3.PM_ADDR
Parked Member Address
MAX：256
4.AR_ADDR
required Parked Mode – to – Active Mode
實體通道(Physical channel)
- 1Mbit/sec
實體通道(頻寬共享)
跳頻技術(Frequency Hopping)
Master和Slave時序同步
- 確認Master與Slave有相同的time block
- 以Master的時序為準
Piconet Formation
• Page - scan
protocol
– to establish links
with nodes in
proximity
Master
Active Slave
Parked Slave
Standby
Scatternet Formation
Physical Link Types
• Synchronous Connection Oriented (SCO)
Link
 Slot reservation at fixed intervals
• Asynchronous Connection-less (ACL)
Link
 Polling access method
藍芽的安全性(Security)
• 無線傳輸的潛在威脅
• 無線傳輸的安全加密
潛在的危險
藍芽的加密技術
1.Initialization key
2.Link key
3.Mutual authentication
4.Encryption key
5.Key stream
6.Encryption of data
Initialization key
IN_RAND
IN_RAND
IN_RAND
PIN
L
PIN
E22
Kinit
E22
Kinit
L
Link key (1)
Kinit
KA = Klink
K
Kinit
KA = Klink
Link key (2)
LK_RANDA
LK_RANDB
LK_RANDA
KAB = Klink
LK_RANDB
ADDRA
E21
ADDRB
E21
LKA
LKB
LKB
LKA
E21
ADDRB
LK_RANDB
KAB = Klink
E21
ADDRA
LK_RANDB
Mutual authentication
ADDRB
AU_RAND
ADDRB
ADDRB
Klink
Klink
E1
E1
AU_RAND
SRES
AU_RAND
ACO
SRES
SRES
ACO
Encryption key
EN_RAND
EN_RAND
EN_RAND
Klink
E3
Klink
E3
ACO
ACO
KC
KC
Key stream
ADDRA
clockMASTER
KC
ADDRA
E0
KCIPHER
E0
clockMASTER
KC
KCIPHER
Encryption of data
KCIPHER
KCIPHER
DATA
DATA
KCIPHER
DATA
KCIPHER
DATA
END